Application of nanoLC–MS/MS to the shotgun proteomic analysis of the nematocyst proteins from jellyfish Stomolophus meleagris

Quality markers of Dajianzhong decoction based on multicomponent qualitative and quantitative analysis combined with network pharmacology and chemometric analysis

INTRODUCTION

Dajianzhong decoction (DJZD), a classic famous prescription, has a long history of medicinal application. Modern studies have demonstrated its clinical utility in the treatment of postoperative ileus (POI). But none of the current quality evaluation methods for this compound is associated with efficacy.

OBJECTIVES

This study aimed to identify the quality markers (Q-Markers) connected to the treatment of POI in DJZD.

METHODOLOGY

Ultra-performance liquid chromatography quadrupole Exactive Orbitrap mass spectrometry (UPLC-Q-Exactive Orbitrap-MS) was used to identify the main constituents in DJZD. Based on the qualitative results obtained by fingerprinting, chemical pattern recognition (CPR) was used to analyse the key components affecting the quality and finally to establish the network of the active ingredients in DJZD with POI.

RESULTS

A total of 64 chemical components were detected. After fingerprint analysis, 13 common peaks were identified. The fingerprint similarity of 15 batches of samples ranged from 0.860 to 1.000. CPR analysis was able to categorically classify 15 batches of DJZD into two groups. And gingerenone A, methyl-6-gingerdiol, 6-gingerol, and hydroxy-β-sanshool contributed to their grouping. Twelve common components interact with the therapeutic targets for treating POI. In addition, the mechanism of this prescription for treating POI may be related to the jurisdiction of the neurological system, the immunological system, and the inflammatory response.

CONCLUSIONS

This integrated approach can accurately assess and forecast the quality of DJZD, presume the Q-Markers of DJZD for POI, and lay the foundation for studying the theoretical underpinnings and exploring the mechanism of DJZD in the treatment of POI.

Protective effect of epigallocatechin-3-gallate (EGCG) on toxic metalloproteinases-mediated skin damage induced by Scyphozoan jellyfish envenomation

Jellyfish stingings are currently raising serious public health concerns around the world. Hence, the search for an effective first aid reagent for the envenomation has been the goal of many investigators in the field. There have been a few previous reports of in vivo as well as in vivo studies suggesting the metalloproteinase activity of scyphozoan jellyfish venom, such as N. nomurai venom (NnV), plays a major role in the pathogenesis. These results have inspired us to develop a metalloproteinase inhibitor as a candidate for the treatment of Scyphozoan jellyfish envenomation. It has been previously demonstrated that the major polyphenol component in green tea, epigallocatechin-3-gallate (EGCG), can inhibit metalloproteinase activity of snake venoms. In fact, plant polyphenols as potential therapeutics have been shown to exert positive effects on neutralizing snake venoms and toxins. In the present study, we found that EGCG significantly inhibits the toxic proteases of NnV in a concentration-dependent manner. Human keratinocyte (HaCaT) and Human dermal fibroblast (HDF) cell culture studies showed that EGCG treatment can protect the cells from NnV-induced cytotoxicity which has been accompanied by the down-regulation of human matrix metalloproteinase (MMP)-2 and -9. Simulated rat NnV envenomation study disclosed that topical treatments with EGCG considerably ameliorated the progression of the dermonecrotic lesions caused by NnV. EGCG also reduced the activitions of tissue MMP-2 and MMP-9, which seem to be crucial players in the dermal toxic responses induced by NnV. Therefore, we propose that EGCG might be an effective therapeutic agent for the treatment of cutaneoous jellyfish symptoms.

Quantitative Proteome Reveals Variation in the Condition Factor of Sea Urchin Strongylocentrotus nudus during the Fishing Season Using an iTRAQ-based Approach

To investigate the variation in the condition factor of the sea urchin Strongylocentrotus nudus (S. nudus), gonads were collected in May (MAY), June (JUN), and July (JUL), at the beginning (AUG-b) and end of August (AUG-e). Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) detection of the gonads revealed an obvious enhancement of the band at about 37 kDa from July, which was identified as transforming growth factor-beta-induced protein ig-h3 (TGFBI) by nanoLC-ESI-MS/MS. Gonadal proteins were identified by isobaric tagging for relative and absolute quantitation (iTRAQ), and regulation of the identified proteins in pairs of the collected groups was observed. A total of 174 differentially expressed proteins (DEPs) were identified. Seven of the DEPs showed significant correlations with both the gonad index (GI) and protein content. These correlations included 6-phosphogluconate dehydrogenase, decarboxylating isoform X2 (6PGD), CAD protein, myoferlin isoform X8, ribosomal protein L36 (RL36), isocitrate dehydrogenase [NADP], mitochondrial isoform X2 (IDH), multifunctional protein ADE2 isoform X3, sperm-activating peptides (SAPs) and aldehyde dehydrogenase, and mitochondrial (ALDH). However, TGFBI had no correlation with gonad index (GI) or protein content. 6PGD, IDH, multifunctional protein ADE2 isoform X3, and ALDH were shown to interact with each other and might play key roles in changing the condition factor of S. nudus gonads.

A genome wide survey reveals multiple nematocyst-specific genes in Myxozoa

Background

Myxozoa represents a diverse group of microscopic endoparasites whose life cycle involves two hosts: a vertebrate (usually a fish) and an invertebrate (usually an annelid worm). Despite lacking nearly all distinguishing animal characteristics, given that each life cycle stage consists of no more than a few cells, molecular phylogenetic studies have revealed that myxozoans belong to the phylum Cnidaria, which includes corals, sea anemones, and jellyfish. Myxozoa, however, do possess a polar capsule; an organelle that is homologous to the stinging structure unique to Cnidaria: the nematocyst. Previous studies have identified in Myxozoa a number of protein-coding genes that are specific to nematocytes (the cells producing nematocysts) and thus restricted to Cnidaria. Determining which other genes are also homologous with the myxozoan polar capsule genes could provide insight into both the conservation and changes that occurred during nematocyst evolution in the transition to endoparasitism.

Results

Previous studies have examined the phylogeny of two cnidarian-restricted gene families: minicollagens and nematogalectins. Here we identify and characterize seven additional cnidarian-restricted genes in myxozoan genomes using a phylogenetic approach. Four of the seven had never previously been identified as cnidarian-specific and none have been studied in a phylogenetic context. A majority of the proteins appear to be involved in the structure of the nematocyst capsule and tubule. No venom proteins were identified among the cnidarian-restricted genes shared by myxozoans.

Conclusions

Given the highly divergent forms that comprise Cnidaria, obtaining insight into the processes underlying their ancient diversification remains challenging. In their evolutionary transition to microscopic endoparasites, myxozoans lost nearly all traces of their cnidarian ancestry, with the one prominent exception being their nematocysts (or polar capsules). Thus nematocysts, and the genes that code for their structure, serve as rich sources of information to support the cnidarian origin of Myxozoa.

Electronic supplementary material

The online version of this article (10.1186/s12862-018-1253-7) contains supplementary material, which is available to authorized users.

Cnidarian peptide neurotoxins: a new source of various ion channel modulators or blockers against central nervous systems disease

Cnidaria provide the largest source of bioactive peptides for new drug development. The venoms contain enzymes, potent pore-forming toxins and neurotoxins. The neurotoxins can immobilize predators rapidly when discharged via modifying sodium-channel-gating or blocking the potassium channel during the repolarization stage. Most cnidarian neurotoxins remain conserved under the strong influence of negative selection. Neuroactive peptides targeting the central nervous system through affinity with ion channels could provide insight leading to drug treatment of neurological diseases, which arise from ion channel dysfunctions. Although marine resources offer thousands of possible peptides, only one peptide derived from Cnidaria: ShK-186, also named dalazatide, has reached the pharmaceutical market. This review focuses on neuroprotective agents derived from cnidarian neurotoxic peptides.

The potential mechanism for Hydroxysafflor yellow A attenuating blood-brain barrier dysfunction via tight junction signaling pathways excavated by an integrated serial affinity chromatography and shotgun proteomics analysis approach

Our previous studies elucidated that hydroxysafflor yellow A (HSYA) exerted anti-inflammatory effects against ischemia stroke by inhibiting TLR4 pathway-mediated signaling transduction. However, only several targets were verified in that limited work. The integrated method of serial affinity chromatography (SAC) and shotgun proteomics analysis (SPA) might be an alternative approach for exploring a potential therapeutic role. SAC was induced to extract specific binding proteins in the brain tissue of 2 h of ischemia stroke mice via HSYA affinity matrices. SPA was conducted by nanoLC-MS/MS, while the identified proteins were mapped on to Gene Ontology and KEGG pathway components analysis. The protection of HSYA for blood-brain barrier in mice with ischemia stroke was assessed with the leakage of Evans Blue. The expression of tight junction proteins of blood-brain barrier: occludin, claudin-5, and ZO-1 were detected with ischemia boundary positive areas staining. The regulation of nonmuscle myosin heavy chain IIA (NMMHC IIA), TLR4-mediated PI3K/AKT/JNK1/2/14-3-3ε/NF-κB p65 signaling pathway were evaluated using western blot analysis. A total of 35 proteins with molecular eights ranging from 27,841.22 to 234,122.79 KD were identified. Gene Ontology annotation and KEGG pathways analysis of the identified proteins were conducted with tight junction and PI3K/AKT signaling pathways. HSYA could significantly reduce the leakage of Evans Blue in mice with ischemia stroke, while attenuating the expression of occludin, claudin-5, and ZO-1. Western blot demonstrated that regulation of NMMHC IIA, TLR4-mediated PI3K/AKT/JNK1/2/14-3-3ε/NF-κB p65 signaling pathway played an essential role in the protective effect of HSYA. The integrated method of SAC and SPA provides the promising explanations for exploring the mechanism underlying blood-brain barrier dysfunction via the tight junction pathway. HSYA could attenuate blood-brain barrier dysfunction in anti-inflammatory patterns in ischemia stroke mice via the tight junction pathway.

Comparative proteomics reveals recruitment patterns of some protein families in the venoms of Cnidaria

Cnidarians are probably the oldest group of animals to be venomous, yet our current picture of cnidarian venom evolution is highly imbalanced due to limited taxon sampling. High-throughput tandem mass spectrometry was used to determine venom composition of the scyphozoan Chrysaora lactea and two cubozoans Tamoya haplonema and Chiropsalmus quadrumanus. Protein recruitment patterns were then compared against 5 other cnidarian venom proteomes taken from the literature. A total of 28 putative toxin protein families were identified, many for the first time in Cnidaria. Character mapping analysis revealed that 17 toxin protein families with predominantly cytolytic biological activities were likely recruited into the cnidarian venom proteome before the lineage split between Anthozoa and Medusozoa. Thereafter, venoms of Medusozoa and Anthozoa differed during subsequent divergence of cnidarian classes. Recruitment and loss of toxin protein families did not correlate with accepted phylogenetic patterns of Cnidaria. Selective pressures that drive toxin diversification independent of taxonomic positioning have yet to be identified in Cnidaria and now warrant experimental consideration.

Recent advances in capillary ultrahigh pressure liquid chromatography

In the twenty years since its initial demonstration, capillary ultrahigh pressure liquid chromatography (UHPLC) has proven to be one of most powerful separation techniques for the analysis of complex mixtures. This review focuses on the most recent advances made since 2010 towards increasing the performance of such separations. Improvements in capillary column preparation techniques that have led to columns with unprecedented performance are described. New stationary phases and phase supports that have been reported over the past decade are detailed, with a focus on their use in capillary formats. A discussion on the instrument developments that have been required to ensure that extra-column effects do not diminish the intrinsic efficiency of these columns during analysis is also included. Finally, the impact of these capillary UHPLC topics on the field of proteomics and ways in which capillary UHPLC may continue to be applied to the separation of complex samples are addressed.

Functional Elucidation of Nemopilema nomurai and Cyanea nozakii Nematocyst Venoms' Lytic Activity Using Mass Spectrometry and Zymography

Background: Medusozoans utilize explosively discharging penetrant nematocysts to inject venom into prey. These venoms are composed of highly complex proteins and peptides with extensive bioactivities, as observed in vitro. Diverse enzymatic toxins have been putatively identified in the venom of jellyfish, Nemopilema nomurai and Cyanea nozakii, through examination of their proteomes and transcriptomes. However, functional examination of putative enzymatic components identified in proteomic approaches to elucidate potential bioactivities is critically needed. Methods: In this study, enzymatic toxins were functionally identified using a combined approach consisting of in gel zymography and liquid chromatography tandem mass spectrometry (LC-MS/MS). The potential roles of metalloproteinases and lipases in hemolytic activity were explored using specific inhibitors. Results: Zymography indicated that nematocyst venom possessed protease-, lipase- and hyaluronidase-class activities. Further, proteomic approaches using LC-MS/MS indicated sequence homology of proteolytic bands observed in zymography to extant zinc metalloproteinase-disintegrins and astacin metalloproteinases. Moreover, pre-incubation of the metalloproteinase inhibitor batimastat with N. nomurai nematocyst venom resulted in an approximate 62% reduction of hemolysis compared to venom exposed sheep erythrocytes, suggesting that metalloproteinases contribute to hemolytic activity. Additionally, species within the molecular mass range of 14–18 kDa exhibited both egg yolk and erythrocyte lytic activities in gel overlay assays. Conclusion: For the first time, our findings demonstrate the contribution of jellyfish venom metalloproteinase and suggest the involvement of lipase species to hemolytic activity. Investigations of this relationship will facilitate a better understanding of the constituents and toxicity of jellyfish venom.

Combined proteomics and transcriptomics identifies sting-related toxins of jellyfish Cyanea nozakii

Jellyfish sting has become a worldwide issue of critical concern to human health and safety in coastal areas in recent decades. Cyanea nozakii is one of the dominant blooming species and dangerous stingers in China. However, it remains unclear how many and what types of toxins are present in the venom. So, we used a combined transcriptomics and proteomics approach to investigate the venom composition of jellyfish C. nozakii. In total 4,608,524 Illumina valid reads were obtained to de novo assemble to 40,434 unigenes in the transcriptomics analysis. And, a total of 311,635 MS/MS spectra with 12,247 unique MS/MS spectra were generated to 1556 homologous proteins in the proteomics analysis. 174 potential toxin proteins were identified, with 27 proteins homology to the toxins from venomous animals, including phospholipase A2, zinc metalloproteinase-disintegrin agkistin, serine protease inhibitor, plancitoxin-1, alpha-latrocrustotoxin-Lt1a, etc. This study described the transcriptomics and venom proteomics of jellyfish C. nozakii for the first time. Our findings provide a comprehensive understanding of the venom composition of C. nozakii. Furthermore, the results may also be very helpful for the discovery of novel bioactive proteins, as well as the development of effective treatments for jellyfish sting in the future.

BIOLOGICAL SIGNIFICANCE

Jellyfish Cyanea nozakii is one of the most dangerous stingers in the coast of china. Hundreds of thousands of people would be stung every year and victims suffered a severe pain, itch, swelling, inflammation, wheal and even more serious consequence. However, it remains unclear how many and what types of toxins are present as well as the relationship between the clinical symptoms and toxins. Our combined transcriptomics and proteomics findings can provide a comprehensive understanding of the venom composition of C. nozakii and will also be helpful for the development of effective treatments for jellyfish sting in the future.

The Acaricidal Activity of Venom from the Jellyfish Nemopilema nomurai against the Carmine Spider Mite Tetranychus cinnabarinus

The carmine spider mite Tetranychus cinnabarinus (T. cinnabarinus) is a common polyphagous pest that attacks crops, vegetables, flowers, and so on. It is necessary to find lead compounds for developing novel, powerful, and environmentally-friendly acaricides as an alternative approach to controlling the carmine spider mite because of the serious resistance and residual agrochemicals in the environment. In addition, the study on the acaricidal activities of marine bioactive substances is comparatively deficient. In the present study, the acaricidal activity of venom (NnFV) from the jellyfish Nemopilema nomurai against the carmine spider mite T. cinnabarinus was determined for the first time. The venom had contact toxicity, and the 24-h LC50-value was 29.1 μg/mL. The mite body wall was affected by the venom, with the mite body having no luster and being seriously shrunken after 24 h. T. cinnabarinus was a potential target pest of NnFV, which had potential as a type of natural bioacaricide. The repellent activity and systemic toxicity of the venom against T. cinnabarinus were also studied. However, NnFV had no repellent activity and systemic toxicity against T. cinnabarinus.

Quantification of emerging micropollutants in an amphipod crustacean by nanoliquid chromatography coupled to mass spectrometry using multiple reaction monitoring cubed mode

An innovative analytical method has been developed to quantify the bioaccumulation in an amphipod crustacean (Gammarus fossarum) of three micropollutants regarded as anthropic-pollution markers: carbamazepine, oxazepam, and testosterone. A liquid-liquid extraction assisted by salts, known as QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) was miniaturised and optimised, so it could be adapted to the low mass samples (approximatively 5mg dry weight). For this same reason and in order to obtain good sensitivity, ultra-trace analyses were carried out by means of nanoliquid chromatography. A preconcentration system by on-column trapping was optimised to increase the injection volume. In order to improve both sensitivity and selectivity, the multiple reaction monitoring cubed mode analyses (MRM(3)) were carried out, validated and compared to the classic MRM. To the best of our knowledge, this is the first time that MRM(3) is coupled to nanoliquid chromatography for the analysis and detection of organic micropollutants <300Da. The optimised extraction method exhibited recoveries superior to 80%. The limits of quantification of the target compounds were 0.3, 0.7 and 4.7ng/g (wet weight) for oxazepam, carbamazepine and testosterone, respectively and the limits of detection were 0.1, 0.3 and 2.2ng/g (wet weight), respectively. The intra- and inter-day precisions were inferior to 7.7% and 10.9%, respectively, for the three levels of concentration tested. The analytical strategy developed allowed to obtain limits of quantification lower than 1ng/g (wet weight) and to establish the kinetic bioconcentration of contaminants within G. fossarum.

Jellyfish Bioactive Compounds: Methods for Wet-Lab Work

The study of bioactive compounds from marine animals has provided, over time, an endless source of interesting molecules. Jellyfish are commonly targets of study due to their toxic proteins. However, there is a gap in reviewing successful wet-lab methods employed in these animals, which compromises the fast progress in the detection of related biomolecules. Here, we provide a compilation of the most effective wet-lab methodologies for jellyfish venom extraction prior to proteomic analysis-separation, identification and toxicity assays. This includes SDS-PAGE, 2DE, gel chromatography, HPLC, DEAE, LC-MS, MALDI, Western blot, hemolytic assay, antimicrobial assay and protease activity assay. For a more comprehensive approach, jellyfish toxicity studies should further consider transcriptome sequencing. We reviewed such methodologies and other genomic techniques used prior to the deep sequencing of transcripts, including RNA extraction, construction of cDNA libraries and RACE. Overall, we provide an overview of the most promising methods and their successful implementation for optimizing time and effort when studying jellyfish.

Tentacle Transcriptome and Venom Proteome of the Pacific Sea Nettle, Chrysaora fuscescens (Cnidaria: Scyphozoa)

Jellyfish venoms are rich sources of toxins designed to capture prey or deter predators, but they can also elicit harmful effects in humans. In this study, an integrated transcriptomic and proteomic approach was used to identify putative toxins and their potential role in the venom of the scyphozoan jellyfish Chrysaora fuscescens. A de novo tentacle transcriptome, containing more than 23,000 contigs, was constructed and used in proteomic analysis of C. fuscescens venom to identify potential toxins. From a total of 163 proteins identified in the venom proteome, 27 were classified as putative toxins and grouped into six protein families: proteinases, venom allergens, C-type lectins, pore-forming toxins, glycoside hydrolases and enzyme inhibitors. Other putative toxins identified in the transcriptome, but not the proteome, included additional proteinases as well as lipases and deoxyribonucleases. Sequence analysis also revealed the presence of ShKT domains in two putative venom proteins from the proteome and an additional 15 from the transcriptome, suggesting potential ion channel blockade or modulatory activities. Comparison of these potential toxins to those from other cnidarians provided insight into their possible roles in C. fuscescens venom and an overview of the diversity of potential toxin families in cnidarian venoms.

Effect of Venom from the Jellyfish Nemopilema nomurai on the Silkworm Bombyx mori L

The silkworm Bombyx mori L. (B. mori) has a significant impact on the economy by producing more than 80% of the globally produced raw silk. The exposure of silkworm to pesticides may cause adverse effects on B. mori, such as a reduction in the production and quality of silk. This study aims to assay the effect of venom from the jellyfish Nemopilema nomurai on growth, cuticle and acetylcholinesterase (AChE) activity of the silkworm B. mori by the leaf dipping method. The experimental results revealed that the four samples caused neither antifeeding nor a lethal effect on B. mori. The sample SFV inhibited B. mori growth after 6 days of treatment in a dose-dependent manner. The samples SFV, DSFV and Fr-1 inhibited the precipitation and synthesis of chitin in the cuticle after 12 and 14 days of treatment. In the case of the four samples, the AChE was significantly improved after 14 days of treatment.

Comparative study of the toxic effects of Chrysaora quinquecirrha (Cnidaria: Scyphozoa) and Chironex fleckeri (Cnidaria: Cubozoa) venoms using cell-based assays

The venoms of jellyfish cause toxic effects in diverse biological systems that can trigger local and systemic reactions. In this study, the cytotoxic and cytolytic effects of Chrysaora quinquecirrha and Chironex fleckeri venoms were assessed and compared using three in vitro assays. Venoms from both species were cytotoxic to fish gill cells and rat cardiomyocytes, and cytolytic in sheep erythrocytes. Both venoms decreased cell viability in a concentration-dependent manner; however, the greatest difference in venom potencies was observed in the fish gill cell line, wherein C. fleckeri was 12.2- (P = 0.0005) and 35.7-fold (P < 0.0001) more potently cytotoxic than C. quinquecirrha venom with 30 min and 120 min cell exposure periods, respectively. Gill cells and rat cardiomyocytes exposed to venoms showed morphological changes characterised by cell shrinkage, clumping and detachment. The cytotoxic effects of venoms may be caused by a group of toxic proteins that have been previously identified in C. fleckeri and other cubozoan jellyfish species. In this study, proteins homologous to CfTX-1 and CfTX-2 toxins from C. fleckeri and CqTX-A toxin from Chironex yamaguchii were identified in C. quinquecirrha venom using tandem mass spectrometry. The presence and relative abundance of these proteins may explain the differences in venom potency between cubozoan and scyphozoan jellyfish and may reflect their importance in the action of venoms.

Exploring the therapeutic potential of jellyfish venom

The venom of certain jellyfish has long been known to be potentially fatal to humans, but it is only recently that details of the proteomes of these fascinating creatures are emerging. The molecular contents of the nematocysts from several jellyfish species have now been analyzed using proteomic MS approaches and include the analysis of Chironex fleckeri, one of the most venomous jellyfish known. These studies suggest that some species contain toxins related to peptides and proteins found in other venomous creatures. The detailed characterization of jellyfish venom is likely to provide insight into the diversification of toxins and might be a valuable resource in drug design.

Firing the sting: chemically induced discharge of cnidae reveals novel proteins and peptides from box jellyfish (Chironex fleckeri) venom

Cnidarian venom research has lagged behind other toxinological fields due to technical difficulties in recovery of the complex venom from the microscopic nematocysts. Here we report a newly developed rapid, repeatable and cost effective technique of venom preparation, using ethanol to induce nematocyst discharge and to recover venom contents in one step. Our model species was the Australian box jellyfish (Chironex fleckeri), which has a notable impact on public health. By utilizing scanning electron microscopy and light microscopy, we examined nematocyst external morphology before and after ethanol treatment and verified nematocyst discharge. Further, to investigate nematocyst content or "venom" recovery, we utilized both top-down and bottom-up transcriptomics-proteomics approaches and compared the proteome profile of this new ethanol recovery based method to a previously reported high activity and recovery protocol, based upon density purified intact cnidae and pressure induced disruption. In addition to recovering previously characterized box jellyfish toxins, including CfTX-A/B and CfTX-1, we recovered putative metalloproteases and novel expression of a small serine protease inhibitor. This study not only reveals a much more complex toxin profile of Australian box jellyfish venom but also suggests that ethanol extraction method could augment future cnidarian venom proteomics research efforts.

Jellyfish venomics and venom gland transcriptomics analysis of Stomolophus meleagris to reveal the toxins associated with sting

Jellyfish Stomolophus meleagris is a very dangerous animal because of its strong toxicity. However, the composition of the venom is still unclear. Both proteomics and transcriptomics approaches were applied in present study to investigate the major components and their possible relationships to the sting. The proteomics of the venom from S. meleagris was conducted by tryptic digestion of the crude venom followed by RP-HPLC separation and MS/MS analysis of the tryptic peptides. The venom gland transcriptome was analyzed using a high-throughput Illumina sequencing platform HiSeq 2000 with de novo assembly. A total of 218 toxins were identified including C-type lectin, phospholipase A₂ (PLA₂), potassium channel inhibitor, protease inhibitor, metalloprotease, hemolysin and other toxins, most of which should be responsible for the sting. Among them, serine protease inhibitor, PLA₂, potassium channel inhibitor and metalloprotease are predominant, representing 28.44%, 21.56%, 16.06% and 15.14% of the identified venom proteins, respectively. Overall, our combined proteomics and transcriptomics approach provides a systematic overview of the toxins in the venom of jellyfish S. meleagris and it will be significant to understand the mechanism of the sting.

BIOLOGICAL SIGNIFICANCE

Jellyfish Stomolophus meleagris is a very dangerous animal because of its strong toxicity. It often bloomed in the coast of China in recent years and caused thousands of people stung and even deaths every year. However, the components which caused sting are still unknown yet. In addition, no study about the venomics of jellyfish S. meleagris has been reported. In the present study, both proteomics and transcriptomics approaches were applied to investigate the major components related to the sting. The result showed that major component included C-type lectin, phospholipase A₂, potassium channel inhibitor, protease inhibitor, metalloprotease, hemolysin and other toxins, which should be responsible for the effect of sting. This is the first research about the venomics of jellyfish S. meleagris. It will be significant to understand the mechanism of the biological effects and helpful to develop ways to deal with the sting.